| US 7,468,859 B2 | ||
| Voice coil motor effective resistance determination | ||
| Fred R. Hansen, Boulder, Colo. (US); and Brian K. Tanner, San Jose, Calif. (US) | ||
| Assigned to Kabushiki Kaisha Toshiba, Tokyo (Japan) | ||
| Filed on May 31, 2006, as Appl. No. 11/421,427. | ||
| Prior Publication US 2007/0279797 A1, Dec. 06, 2007 | ||
| Int. Cl. G11B 5/596 (2006.01) | ||
| U.S. Cl. 360—78.14 [360/78.04] | 17 Claims |
| 1. A method of determining a correction factor for a voice coil motor of a disk drive device, the method comprising:
driving a current through the voice coil motor during a seek operation;
measuring actuator velocity;
measuring back electromotive force (EMF) voltage during the seek operation; and
calculating the correction factor as a function of the actuator velocity and measured back EMF voltage, wherein the correction
factor is calculated via multiple measurements at more than one voice coil motor operating point, wherein the actuator velocity
is estimated using the correction factor, and wherein the correction factor is multiplied by the voice coil motor current
to cancel voice coil motor resistance errors in measurement of the back EMF voltage.
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